Notification sound looping topic

When I receive a notification, the sound the phone makes to signify this plays continuously until I unlock the phone and pull down the status bar. I know that this has happened with both photo auto backup notifications and also YouTube notifications. As far as I know, hangouts did not have the same effect when I received an sms. My N6 bootloader is unlocked and my phone is rooted.

Any help is greatly appreciated, thanks!